Carburetor float valve



Dec. 26, 1967 c. PARKER 3,360,003

` CARBURETOR FLOAT VALVE Filed May 14, 1965 YBY United States Patent O3,360,003 CARBURETOR FLOAT VALVE Leland C. Parker, deceased, late ofRochester, N.Y., by

Laura H. Parker, executrix, Rochester, N.Y., assignor to General MotorsCorporation, Detroit, Mich., a corporation of Delaware Filed May 14,1965, Ser. No. 456,006 1 Claim. (Cl. 137-448) ABSTRACT OF THE DISCLOSUREA-triangular valve member operated by a fuel level responsive floatilexes against incoming fuel pressure and the force of a biasing springto provide increasing areas for fuel flow.

This invention relates to carburetors and more particularly to aflexible float valve for a carburetor fuel bowl. f

Theilow of fuel into the fuel bowl of a carburetor is normallycontrolled by a valve which is operated by a lloat located within thefuel bowl. The float is adjusted to close the valve when the fuel in thebowl reaches the desired level and to open the valve when the fuel dropsbelow this level. When the valve is arranged to be biased closed `by thepressure of the incoming fuel, the force produced by the weight of theiloat and increased by suitable linkage must be sullicient to open thevalve against this pressure.

Present day automotive engines require carburetors which will supply anair fuel mixture at a high rate of flow. This requirement can be met byincreasing the size of the fuel bowl and the size of the valve whichadmits fuel to the bowl. However, in some applications, spacelimitations or other factors limit the increase in size of the fuel bowlto less than required.

Limitations on the size of the fuel bowl also limit the size of thelloat and linkages which may be used to operate the valve. In some casesthe force exerted by the float may be insufficient to open the largearea valve needed to satisfy the fuel requirements of the carburetor.

The present invention overcomes this diiliculty -by providing a flexiblefloat valve member which may be opened by a very small opening forceapplied lby the float and linkage since only a portion of the valvemember need be opened to admit fuel.

When a rigid valve member is made large enough to supply the fuelrequirements, initial movement of the valve to open position oftenpermits excess fuel to flow to the fuel bowl before the regulating valveis closed. This dilllculty is also overcome since the entire valvemember of this invention need not be opened to admit fuel to the fuelbowl but only a portion thereof need be opened to permit a small amountof fuel to ilow into the fuel bowl and thus accurately control the levelof the fuel.

One feature of this -invention is that it provides an improved iloatvalve for controlling the flow of fuel to the fuel bowl of a carburetor.

Another feature of this invention is that it provides a lloat valve fora carburetor which may be opened by a small opening force and yet permita high rate of fuel llow.

A further feature of this invention is that it provides a flexible floatvalve member for a carburetor having gradually increasing areas thereofmovable away from gradually increasing areas of a valve seat opening toprovide accurately controlled gradually increasing rates of flow.

Yet another feature of this invention is to provide a flexiblecarburetor fuel Ibowl inlet valve member having a small portion whichwill easily bend away from the 3,360,003 Patented Dec. 26, 1967 valveseat opening upon application of a small amount of pressure thereto andpermit a low rate of fuel llow to the fuel bowl.

These and other features of this invention will be apparent from thefollowing specification and drawings wherein:

FIGURE 1 is a partly broken away elevational view of a carburetorembodying a valve according to this invention;

FIGURE 2 is an enlarged view taken generally along the plane indicatedIby line 2 2 of FIGURE l with parts broken away to show the valve seat;and

FIGURE 3 is an exploded view illustrating the components of the valvearrangement.

A carburetor designated generally 10 includes a body 12 and cover 14. Afuel bowl 16 is formed by a portion of the body and cover and contains afloat 18. The lloat is secured to one end of an arm 20 which ispivotally mounted on body 12 by pin 22. The other end of the arm engagesone end of a plunger 24, the other end of which is adapted to exert anopening pressure on a flexible valve member designated generally 26which is part of the carburetor float valve designated generally 28.Pressurized fuel supplied by a fuel pump, not shown, flows through thefuel line 30 to the fuel inlet chamber 32. The fuel in the fuel inletchamber exerts a closing pressure on the valve member 26 and thusincreases the pressure needed to open the valve member. As the fuellevel in the fuel bowl drops, the lloat also drops pivoting the arm 20vabout the pin 22 and exerting an upward pressure on the valve member 26through the plunger 24. When the valve opens in response to pressure ofthe plunger, fuel flows to the fuel bowl to restore the fuel to itsoriginal level and raise the float to its original position so thatvalve 28 may be closed as will be described later.

The lloat valve 28 includes the flexible valve member 26 which isgenerally triangularly shaped and generally complementary in shape to avalve opening 34 which is defined or bounded by a raised wall 36, theupper surface of which provides a valve seat 38. A generally T-shapedspring 40 has the head thereof overlying a base portion of the valvemember 26, with the spring and valve member being secured at 42 adjacenta base wall portion of the wall 36. The shank of the spring 40 biasesthe valve member 26 to a closed position in engagement with the seat 38.It will be noted that the valve mmeber 26 has the sides thereof spacedslightly inwardly of the side wall portions of wall 36 and the apexthereof provided with a small generally rectangularly shaped tab orportion 44 which overlies the apex of the side Wall portions of wall 36.The shank of the spring 40 engages only a portion of the tab 44. Theplunger 24 engages the valve member 26 immediately adjacent the tab 44thereof.

When the fuel level in the fuel bowl drops, the plunger 24 will bendback the tab 44 and an adjacent small area portion of the valve member26 to thereby permit fuel to llow into the bowl. lf the fuel level isonly slightly below the desired level, a small amount of fuel willrestore the fuel to the desired level. Only a small portion of the valvemember 26 need be opened to admit this small amount of fuel and restorethe desired level without overlllling the bowl. Since the force exertedby the float 18 depends on the fuel level in the bowl, it can be seenthat where only a slight amount of fuel is needed to lill the bowl tothe desired level, the arm 20 will exert only a slight force and sinceonly a small area portion of the valve portion 26 need be opened thisforce issullicient. Further, since only a small area portion of thevalve member 26 is opened, the llow of fuel into the bowl can beaccurately controlled.

The shape of the valve member 26 and the opening 34 provide graduallyincreasing areas to in turn provide gradually increasing rates of flowto the fuel bowl. Thus, depending on the level of the fuel in the bowland the relationship of this level to the desired level, the valvemember 26 and opening 34 can be opened with respect to each other toprovide the desired rate of flow necessary to return the level of thefuel in the bowl to that desired.

It is desirable that the valve member and opening be formed in atriangular shape or other shapes which have gradually increasing areas.This permits the plunger to be located so that it contacts a small areaportion of the valve member to open a complementary small area portionof the opening. It is also desirable that the plunger 24 be located sothat it will contact the valve member 26 remote from the secured portionthereof. This permits a small area portion of the valve to be opened andresults in better regulation of the liquid level in the fuel bowl.

Thus an improved carburetor lloat valve has been provided.

What is claimed is:

An internal combustion engine carburetor having a body defining a fuelbowl chamber, a fuel inlet chamber and an inlet port opening from saidinlet chamber to said bowl chamber, a raised wall extendingcircumferentially about said port on the inlet chamber side thereof toform a valve seat having a generally triangular shape, a flexible valvemember overlying said raised wall, said valve member having a shapewhich generally conforms to the shape of said valve seat and whichcoacts with said valve seat to control fuel owing from said inletchamber to said fuel bowl chamber, means securing a base portion of saidvalve member to said body adjacent a base portion of said valve seat,said valve member having an apex portion opposite said base portion andincluding a tab portion extending outwardly from said apex portion awayfrom said base portion, a leaf spring member overlying said valve memberand secured at one end adjacent the base portion of said valve seat andextending over said tab portion of said valve member, fuel levelresponsive float means disposed in saidvbowl chamber, a pivotal armsecured at one end to said float means, and a reciprocable plungeroperated by said arm for opening said valve member in response to adecrease in fuel level in said bowl chamber, said plunger bearing onlyagainst and exerting a force on the apex portion of said valve memberfor flexing said valve member against the pressure of fuel in said inletchamber and against the force of said spring member whereby only a smallportion of said valve member may be unseated initially to permit fuel toflow at a low rate into said fuel bowl chamber and whereby increasingportions of said valve member may be unseated subsequently to permitfuel to flow from said inlet chamber to said fuel bowl chamber at higherrates of flow.

References Cited UNITED STATES PATENTS 1,699,954 1/1929 Connell et al.137-527 1,850,850 3/1932 Peterson 251-207 2,216,000 9/1940 Crawford137-173 2,675,025 4/1954 Wynkoop 137-625.12

WILLIAM F. ODEA, Primary Examiner.

D. R. MATTHEWS, Assistant Examiner.

